3. Pothoidium Schott, Aroideae. 26. 1856.
假石柑属 jia shi gan shu
Authors: Heng Li & Peter C. Boyce
Shrubs, climbing. Branches extra-axillary. Leaves simple, distichous, petiolate; petiole elongated, leaflike, flattened, veins parallel; leaf blade triangular-lanceolate, short, with parallel veins. Inflorescences in axil of leaves; bractlike cataphylls 1 or 2. Spathe deciduous, short. Spadix cylindric. Flowers bisexual but plants functionally dioecious; tepals 6, with vaulted-truncate apex; stamens 3-6, anthers oval, longitudinally dehiscent; ovary obovoid, 1-loculed, ovule solitary, subbasal, stigma sessile. Berry ovoid, acute. Seed oblong, without endosperm.
One species: China (Taiwan), Indonesia (Maluku, Sulawesi), Philippines.
Pothoidium is similar to Pothos repens but differs in being functionally dioecious, by the branching inflorescences, and by its unilocular ovary and solitary ovule. Pothoidium has functionally unisexual spadices arranged seemingly in panicles and maturing sequentially. The structure of the fertile shoots is not yet clearly understood; however, it is possible that they are developed by the reduction of all the leaves of a leafy fertile shoot system to minute prophylls and cataphylls and that the panicle-like synflorescence is hence to be regarded as an aggregate structure. Pothos repens and Pothoidium are vegetatively almost identical. Depauperate flowering specimens of Pothoidium greatly resemble robust plants of Pothos repens. Interpretation of Pothoidium inflorescences suggests that P. lobbianum is functionally dioecious. "Male" spadices have flowers with prominently visible anthers and an apparently sterile ovary. "Female" spadices have flowers with a large unilocular fertile ovary and no stamens. Flowers of Pothos species are always bisexual with a 3-locular ovary.
